All synthetic materials which contact blood are thrombogenic and activate processes such as fibrin coagulation, platelet adhesion, and complement activation. Because of these observations, numerous investigations have been conducted to develop nonthrombogenic materials. These include chemical modifications of the natural surface by the addition of hydrophilic moieties or immobilization of biologically active substrates. An alternative approach would be to incorporate anionic moieties into the polymer matrix, which is reported to result in a highly antithrombogenic surface. The goal of this Phase I research project is to utilize BSI's proprietary photoimmobilization technology to covalently immobilize photoreactive polyacrylamide-polysulfonate polymers onto various biomaterials. These polysulfonate coatings will potentially affect protein and platelet adhesion and lead to the development of long-lasting antithrombogenic surfaces.